The EX engine series from Subaru Industrial Power Products includes nine models total, with power ranges from 4.5 to 14 horsepower. All engines in this line are four-cycle, single-cylinder, air-cooled engines. Technology This line is Subaru's first to utilize chain-driven overhead cam (OHC) technology, and the first to utilize OHC technology in the industrial air-cooled small engine market. The significance of Overhead Cam technology is that it's been proven to enhance engine performance. The technology allows the intake and exhaust valves being positioned for optimum engine performance, which offers lower resistance for the air/fuel mixture flow. Overhead Cam engines also have fewer moving parts and produce less mechanical noise than competitive technologies. They also offer better cooling performance to combat overheating. Models With one exception, all engines in the EX line are carbureted. The 7 horsepower EX21 EFI is an electronic fuel injection engine. The engine line was first introduced with four models in 2001, and has grown to include nine models. EX Engine Models EX13 – 4.5 horsepower EX17 – 6 horsepower EX21 – 7 horsepower EX27 – 9 horsepower EX30 – 9.5 horsepower EX35 – 12 horsepower EX40 – 14 horsepower EX21 EFI – 7 horsepower EX27 All Season – 9 horsepower Applications The engines can be used on construction equipment such as soil compactors, pressure washers, generators, water pumps, air compressors, log splitters, lawn and turf seeders and chippers/shredders. The engines have also found to work well on go-karts. References External links 2021 Subaru Impreza Subaru engines